[DISC] Add runtime configuration for OpenHAB (#1658)

* [DISC] Add runtime configuration for OpenHAB

Add an MQTT configurable system key "ohdiscovery" for OpenHAB auto discovery

* Docs and environments update

docs/integrate/openhab2.md

@@ -7,9 +7,6 @@ So as to use the autodiscovery function you need to have:
 * The Jinga transformation addon installed
 * The Json transformation addon installed
 
-You need to set `OpenHABAutoDiscovery` to true into `config_mqttDiscovery.h`
-`#define OpenHABDiscovery true`
-
 ::: tip
 If you are connecting to BLE devices it is highly recommended to set `filterConnectable` to `true` in [BT configuration](../use/ble.md#advanced-filter-out-connectable-devices). Otherwise you may encounter incomplete data.
 :::

docs/integrate/openhab3.md

@@ -64,7 +64,7 @@ Bravo👏, second step done! Now let's add the Jinja transformation service.
 Second step done!
 
 ## Upload OpenMQTTGateway to an ESP32
-[Upload OpenMQTTGateway from the web](../upload/web-install.md) by selecting `esp32dev-ble-openhab`
+[Upload OpenMQTTGateway from the web](../upload/web-install.md) by selecting the environment corresponding to your need.
 
 Or use another upload method from the Upload section.
 
@@ -75,6 +75,10 @@ Or use another upload method from the Upload section that requires credentials b
 
 You should see the gateway connected to your broker by checking with an MQTT client like MQTT Explorer.
 
+To make the auto discovery compatible with OpenHAB you have to send the following command with a retain flag.
+
+`mosquitto_pub -t "home/OpenMQTTGateway/commands/MQTTtoSYS/config" -m '{"ohdiscovery":true}'`
+
 ## Adding the things
 1. From the Administration click on "Things" under "Settings", you should see a number in the INBOX button